Fluid flow control manifolds and devices

ABSTRACT

A valve manifold and a modular valve which may be used in the assembly thereof or used separately therefrom. When the valve is mounted in any one of four positions, four different combinations of functions are possible. No additional parts are required to mount the valve in any of the four positions. All valves may be identical or some may be normally open and some normally closed. Half O-ring grooves permit the use of two positions. Mounting symmetry is required in any case. Two seals permit either pneumatic or hydraulic use. Tandem operation of two valves with a single solenoid is accomplished through the use of rods slidable through the valve body. Higher pressure ratings may be achieved in alternative embodiments.

United States Patent [191 Greenwood et a1.

[ FLUID FLOW CONTROL MANIFOLDS AND DEVICES International Telephone andTelegraph Corporation, New York, N.Y.

Assignee:

Filed: Feb. 12, 1973 Appl. No; 331,630

Related US. Application Data Divism 1. March 1, 1972, 1?? P-.., l47,.62

[56] References Cited UNITED STATES PATENTS 5/1958 Gray 137/271 12/1966Fox l37/625.64 X 2/1967 Churchill l37/625.65 3/1969 Ray 251/129 June 11,1974 3,534,772 10/1970 Stampfli 137/625.65 X 3,538,954 ll/l970 Fagerlie251/129 X 3,542,333 11/1970 Stampfli 251/85 3,559,686 2/1971 Hoffman137/625.64 3,677,298 7/1972 Greenwood et a1. l37/625.64

Primary Examiner-l-lenry T. Klinksiek Assistant Examiner-Robert .1.Miller Attorney, Agent, or Firm-A. Donald Stolzy 5 7 ABSTRACT A valvemanifold and a modular valve which may be used in the assembly thereofor used separately therefrom. When the valve is mounted in any one offour positions, four different combinations of functions are possible.No additional parts are required to mount the valve in any of the fourpositions. All valves may be identical or some may be normally open andsome normally closed. l-lalf O-ring grooves permit the use of twopositions Mounting symmetry is required in any case. Two seals permiteither pneumatic or hydraulic use. Tandem operation of two valves with asingle solenoid is accomplished through the use of rods slidable throughthe valve body. Higher pressure ratings may be achieved in alternativeembodiments.

1 Claim, 10 Drawing Figures ma I 9/ /05/ 82 73 3 a7 8/ 7a a? N9 #8 ms/22 /2,: 26 424 oo PATENTEDJUH 1 1 1974 SHEET 10F 3 C W. lNDEB PO/QTFROM PATENTEDJUNH m4 3.815633 SHEET 2 OF 3 FLUID FLOW CONTROL MANIFOLDSAND DEVICES This application is a division of copending parentapplication Ser. No. 230,891 filed Mar. 1, 1972, now U.S. Pat. No.3,747,623. The benefit of the filing date of said copending applicationSer. No. 230,891 is, therefore, hereby claimed for this application.

BACKGROUND OF THE INVENTION This invention relates to the fluid flowcontrol art, and more particularly, to a valve manifold, and a valvewhich may be used within or without the manifold.

Although the present invention is new, the broad idea of manifoldinguniversal type three-way modular valves is old in the art. However, suchmanifolds require a spacer between valves and the location of a seal inone of two alternate positions in two respective holes through thespacer. Such prior art manifolds are suitable for use in pneumaticsystems but are unsuitable for use in hydraulic systems.

Prior art valve manifolds lack versatility in a number of other ways aswell. For example, the exhaust port from each valve body can be locatedin only one position. Further, a prior art modular valve can be operatedto perform only one function. That is, it can be used only as anormally. closed valve or only as a normally open valve, but not aseither one.

SUMMARY OF THE INVENTION In accordance with the present invention, theabovedescribed and other disadvantages of the prior art are overcomebyproviding a new threeway valve including two valves operated in tandem,or equivalent.

It is a feature of the invention that one of the tandem valves isoperated by the other through rods slidable in holes in the valve body.This arrangement is similar to, but different from, that disclosed incopending application Ser. No. 101,330 filed Dec. 24, 1970, by R.Greenwood and J. P. Etcheverry for VALVE, now U.S. Pat. No. 3,677,298.

It is another feature of the invention that the same said new valve oranother valve can be employed as a modular valve, wherein the modularvalve may be rotated about a first axis to reverse the position of thecylinder port thereof. Port alignment and port symmetry of one type arerequired in this case. A half O-ring groove or equivalent is alsorequired.

It is still another feature of the invention that a modular valve isprovided which may be rotated about the first axis or a second axisperpendicular thereto to convert the modular valve from normally open tonormally closed or vice versa. This also requires port symmetry andalignment of a type which may be the same as or different from that ofsaid one type. In any case, one embodiment of the modular valve of thepresent invention can be left alone or rotated l80 about either one orboth of said first and second axes to any one of four positions. Thisvalve then performs any one of four combinations of functions. Forexample, the four functions may be: (I) normally closed-cylinder portright, (2) normally closed-cylinder port left, (3) normallyopen-cylinder port right, and (4) normally open-cylinder port left.

A further feature of the invention resides in the use of at least twoseals. The manifold and valve of the present invention may, for thisreason, be employed in hydraulic as well as pneumatic systems.

It is still another feature of the present invention that one modularvalve thereof may be easily mounted in either a normally open or anormally closed position.

The above-described and other advantages of the present invention willbe better understood from the following detailed description whenconsidered with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings which are to beregarded as merely illustrative:

FIG. 1 is a perspective view of a manifold including a plurality ofsolenoidvalves;

FIG. 2 is a vertical sectional view, partly in elevation, indicating howthe position of a piston may be controlled by a three-way valve;

FIG. 3 is a top plan view of a valve body constructed in accordance withthe present invention;

FIG. 4 is avertical sectional view of a normally closed solenoid valvehaving the body shown in FIG. 3 and taken on the line 44 shown in FIG.3;

FIG. 5 is a vertical sectional view of the valve shown in FIG. 4 buttaken on the line 5-5 shown in FIG. 3;

FIG. 6 is a view similar to FIG.-4 of a normally open solenoid valve;

FIG. 7 is a view similar to FIG. 5 but of the normally open solenoidvalve of FIG. 6;

FIG. 8 is a transverse sectional view of the solenoid valve taken on theline 88 shown in FIG. 7;

FIG. 9 is a topplan view of a conventional rubber O- ring seal; and

FIG. 10 is a sectional view of the seal taken on the line l0l0 shown inFIG. 9.

DESCRIPTION OF THE PREFERRED EMBODIMENTS In FIG. 1, a valve manifold 19is illustrated including solenoid valves 20, 21, 22, 23, 24,25, 26 and27. All of these valves may be identical. However, note will be takenthat the orientation of solenoid valves 23, 24 and 25 are different fromthose of solenoid valves 20, 21, 22, 26 and 27. Solenoid valves 20, 21,22, 26 and 27 are all oriented the same way. Solenoid valve 23 isoriented different from any of the other solenoid valves illustrated inFIG. 1. The same is true of solenoid valves 24 and 25.

All of the solenoid valves illustrated in FIG. 1 are fixed together byfour bolts 28, only three of which are shown in FIG. 1. A

The valves 20-27 are'modular valves. Each one may, thus, be oriented inany one of four positions independent of the orientation of the others.f

Solenoid valves 20, 21, 22, 23, 24, 25, 26 and 27 have valve bodies 30,31, 32, 33, 34, 35, 36 and 37, respectively. Solenoid valves 20, 21, 22,23, 24, 25, 26 and 27 also have solenoid actuators 40, 41, 42, 43, 44,45, 46 and 47, respectively. Each of the actuators 40-47 may beindependently actuated to move a piston for control purposes, forexample. That is, the piston may open or close a much larger valve or dosome" other work. I

Each of the valve bodies 30-37 has a cylinder port. However, due to theorientation of the solenoid valves in FIG. 1, only two cylinder portsare shown. These ports are ports 53 and 55 in valve bodies 33 and 35,respectively.

As will be explained, each valve body shown in FIG. 1 has a pair ofinlet ports and a pair of exhaust ports. The inlet ports are connectedto a common inlet pipe 68. The exhaust ports are connected to a commonexhaust pipe 61. Thus, as shown in FIG. 2, if a pipe 62 connected fromcylinder port 53 of valve body 33 in one position of valve 23, hydraulicfluid under pressure is admitted to the interior of cylinder 63 abovepiston 64 to depress piston 64 and do the desired work. On the otherhand, with the valve 23 in its other position, the interior of thecylinder 63 above piston 64 is exhausted through-pipef61, and a spring65 returns piston 64 to its uppermostposition. A shaft 66 is slidablyguided through a hole 67 in cylinder 63 and is connected to whateverdevice that it is employed to operate.

In FIG. 1, note will be taken that all of the cylinder ports of valvebodies 30, 31, 32, 34, 36 and 37 are on the sides opposite those shownin FIG. 1. It is, therefore, an advantage of the invention that thecylinder ports may be employed on either side of the manifold 19.

. The substantial versatility of the manifold 19, shown in FIG. 1; maybe better understood from the following further description. If each oneof the valves shown in FIG. 1 is a normally closed valve in oneposition, it may be converted to a normally open valve in anotherposition ororientation. The reverse is also true. That is, if it isanormally open valve inv oneposition, it may be converted to anormallyclosed valve in another position. The reason why it may be desirable tolocate one of the valves shown in FIG. 1 in any one of four positionsisthat there are four combinations of cylinder port positions and open andclosed positions. That is, for example, a cylinder port right positionwith a normally closed position, a cylinder port right position with anormally open position, a cylinder port left position with a normallyclosed position, and a cylinder port left position with a normally openposition.

For example,'assume that valves 20, 21, 22, 26 and 27 are normallyclosed in the cylinder port left position. Then. solenoid valve 23 is ina normally open cylinder port right position. Solenoid valve 24 is thenin a normally open cylinder port left position. Solenoid valve 25 is ina normally closed cylinder port right position. The last four sentencesare also true if each of the phrases normally closed is replaced withthe phrase normally open and vice versa.

A valve body 68 is shown in FIG. 3. All of the valve bodies shown inFIG. 1 may be identical to valve body 68, if desired. The same is trueof .valve'bodies 69 and 70 shown in FIGS. 4, 5, 6 and 7. A valve 71 isshown in FIGS. 4 and 5. A valve 72 is shown in FIGS. 6 and 7. Valve 71is a normally closed valve when oriented in the position of valve shownin FIG. 1. Valve 72 is normally open when located in the position ofvalve 20 in FIG. I.

If desired, all of the valves shown in FIG. 1 may be identical to valve71. Alternatively, all the valves shown in FIG. 1 may be identical tovalve 72. Still further,

some of the valves shown in FIG. 1 may be identical to valve 71 andother of the valves shown in FIG. 1 may be identical to valve 72.

As may be evident, as many valves may be employed in one manifold asdesired. For example,one valve may be employed, or two or more or anynumber of valves may be employed including three, four, five, six,seven, eight or more valves.

As shown in FIG. 4, valve 71 has four holes 73 therethrough throughwhich the four bolts 28 project and clamp the valve bodies together.

As shown in FIG. 5, valve body 69 has two inlet ports 74 and 75 whichare in communication with each other. Fluid under pressure maybe-supplied to either one of the inlet ports 74 and 75. This fluid underpressurewill then travel through a passage 76 in valve body 69. Bothinlet ports 74 and 75 are in communication with each other and withpassage 76. Part of the versatility of valve 71 resides in the use ofthe two inlet ports 74 and 75. Moreover, when a plurality of such valvesare clamped together in a manifold such as manifold 19 with or withoutvalves such as valve 72, inlet pressure is communicated to all valvessimultaneously. This is also true of pressure supplied to two exhaustports 77 and 78 in valve body 69,- shown in FIG. 5. Thus,.both exhaustports 77 and 78 are in communication with each other and with a passage79. i

A hollow cylinder 80 is fixed to valve body 69 and provides a valve seatat 81 against which a rubber disc 82 rests to close the opening incylinder 80. The opening in cylinder 80 is in communication with passage76, as shown in FIG. 4. I

Similarly, a cylinder 83 is fixed to valve body 69 providing a valveseat at 84 against which a rubber'disc 85 can rest, cylinder 83 beinghollow and having its interior, which is open at both ends, incommunication with passage 79.

An aluminum fitting 87 is rolled over the lower flaring end 88 of aferromagnetic plunger'89 at 90. Fitting 87 has a flange 91 which abuts aflange 92 on disc 82 to retain it tightly against the lower end 88 ofplunger 89. A helically coiled spring 93 is positioned in a hole 94 inplunger 89 to maintain disc 82 normally in engagement with valve seat 81when a solenoid winding 95 around plunger89 is deenergized.

Valve 71 includes an actuator 96. Actuator 96 may include winding 95 andother structures shown in FIG. 4'

Plunger 89 has vent holes 97 and 98 between the exterior thereof andhole 94, Plunger 89 is slidable on a pin 99 that abuts the upper end 100of arecess 101 inside a member 102. Member 102 has a flared flange 103which is pressed against valve body 69. and clamped thereto by athreaded member 104. An O-ring seal 105 is provided between flange 103and valve body 69. An O-ring seal 106 is provided between flange 103 andmember 104. A ferro-magnetic yoke 107 has holes 108 through which member102 projects. Winding 95 surrounds member 102 between the upper andlower legs of yoke 107 at 109 and 110, respectively.

Washers are provided at 111, 112 and 113, washer 113 being a lockwasher. A nut 114 is threaded onto a o reduced diameter threaded upperend of member 102 81. Rods 117 and 118 which are slidable respectivelyin holes 119 and 120 in valve body 69, abut the lower surface of fitting87. Rods 117 and 118 are press fit in a carrier 121. Rods 117 and 118are, thus, fixed relative to carrier 121. Carrier 121 has a flange 122which retains disc 85 therein by engagement thereof with a flange 123 onvalve disc 85. A snap ring 124 in carrier 121 prevents downward movementof valve disc 85 relative to carrier 121. A helically coiled spring 125is then trapped between an upper surface 126 of a closure member 127 andsnap ring 124. Closure member 127 is threaded into valve body 69 andsealed therewith by an O-ring seal 128, closure member 127 havingspanner wrench holes 129 and 130.

When winding 95 is deenergized, the force of spring 93 is such that theforce of spring 125 is overcome and valve disc 82 is placed inengagement with valve seat 81, and valve disc 85 does not touch and isspaced from seat 84. However, when winding 95 is energized, themagneticforce of attraction produced by winding 95 moves plunger 89upwardly, as viewed in FIG. 4, to space disc 82 from valve seat 81. Thisrelieves the force transmitted by rods 117 and 118 to carrier 121 andpermits spring 125 to cause valve disc 85 to engage seat 84 and closeoff the interior of cylinder 83. I

In FIG. 4, note will be taken that a chamber exists at 131 whichsurrounds valve disc 82 and fitting 87. Similarly, a chamber 132 alwayssurrounds valve disc 85 and carrier 121. Both of the chambers 131 and132 are always in communication with each other and with a cylinder port133. Chamber 132 is in communication with cylinder port 133 through apassage 134. However, chambers 131 and 132 are in communication witheach other through holes 119 and 120. Moreover, chambers 131 and 132 arealso in communication with each other through passages 135 and 136,shown in FIG. 5. Comparison of FIGS. 3, 4 and 5 will reveal that valvebodies 68 and 69 have a great deal of symmetry. Passage 134 iskidneyshaped. Hole 119 and passage 135, thus, both open into passage 134. Apassage 137 is also provided at the opposite end of the body. Passage137 is also kidney shaped and may be identical in shape and size topassage 134. Both hole 120 and passage 136 open into passage 137. v

Considerable confusion in reading the drawings may be avoided bycarefully noting that the section lines 4-4 and 5-5, shown in FIG. 3,are not straight lines. For example, starting from the left-hand side ofthe section line 4-4 in FIG. 3, the section is straight through themiddle of the valve body 68. The section then abruptly jumps 45 degreesin a clockwise direction through the center of the valve and in acounterclockwise direction 45 through the center of the right-hand sideof the valve body 68. Cylinder port 133 may be centrally located, butnot necessarilyLSince kidneyshaped passage 134 extends around the plug aconsiderable distance, e.g. at least 45 on each side of the bore axis ofcylinder port 133, ample interception is created to-receive inletpressure through passage 134. Rods 117 and 118, however, are located ona 45 line. Holes corresponding to holes 119 and 120 in FIG. 4 areindicated at 119' and 120' in FIG. 3. Passages corresponding to passages135 and 136 in FIG. 4 are indicated at 135' and 136' in FIG. 3. Akidney-shaped passage 137' is indicated in FIG. 3 which corresponds tokidney-shaped passage 137 in FIGS. 4 and 5.

Due to the fact that the section 4-4 is taken looking upwardly as viewedin FIG. 3, and section 5-5 is taken looking to the right as viewed inFIG. 3, passage 134 is shown to the left of passage 137 in FIG. 4, andpassage 137 is shown to the left of passage 134 in FIG. 5.

As stated previously, ports 74 and 75, shown in FIG. 5, are incommunication with one another. However, due to the 45 rotation of thesection lines shown in FIG. 3, it is to be especially noted that neitherof the ports 74 and 75, shown in FIG. 5, are in communication with anyof the passages 134, 135, 136 and 137. The same is true of ports 77 and78.

Ports 74, 75, 77 and 78 have O-ring grooves 138, 139, 144 and 145 spacedtherefrom, respectively, but concentric therewith. If desired, each ofthe O-ring grooves 138-145 may be of the same shape and size and have adisc approximately equal to one-half the small diameter of an O-ring.

A conventional O-ring 146 is shown in FIG. 9 having a diameter indicatedat D. A sectional view of the O- ring 146 is shown in FIG. 10 having adiameter, d. The dimension, d, is hereby defined for use herein and inthe claims to be the small diameter of an O-ring.

When joined together, as described previously, a valve body 69' havingan actuator mounted thereon may be clamped to the right-hand face 147 ofvalve body .69, as shown in FIG. 5, with O-rings at 148 and 149. A valvebody may,-thus, be clamped to either the right-hand side 147 or theleft-hand side 150 of valve body 69, as shown in FIG. 5. Alternatively,valve bodies may be clamped to both sides of valve body 69 with suitableO-rings provided wherever one side of one valve body is clamped to oneside of another valve body. A manifold may be created such as manifold19 of any length in this manner.

If desired, all ports the same as or similar to ports 74, 75, 77 and 78may or may not be threaded. Any such threading may be employed toconnect conventional fittings such as indicatedat 151 and 152 in FIG. 1.The same is true of the threading of cylinder port 133, shown in FIG. 4.

In FIG. 4, in the position shown, spring 93 is always in compression.

In FIG. 6, valve 72 may be identical to valve 71 including and belowvalve seat 81. However, valve 72 includes an actuator 153 having asolenoid winding 154 which, when deenergized, permits a valve disc 155to be spaced from valve seat 81.

Actuator 153 includes a housing 156 which is fixed to valve body 70. Amember 157 is threaded into the top of valve body 70 and sealed theretoby an O-ring 158. Member 157 carries a shading ring 159 fixed thereto. Acover 160 is fixed to member 157. A nut 161 is threaded to cover 160 andholds down the assembly including spacers 162,163 and 164; housing 156;spacers 165, 166 and 167; winding 154 and spacer 168.

A ferromagnetic plunger 169 is slidable in cover 160 to depress theupper end of a member 170 slidable in member 157. Member 170 has aflange 171 which abuts a flange 172 on disc 155 to retain disc 155therein. A spring 153 is located in a recess 174 in memher 170 to biasdisc flange 172 against member flange 171. Spring 173. permitsovertravel of member 170 when disc 1S5 engages valve seat 81.

The section shown in FIG. 8 is taken through FIG. 7 as though the viewof FIG. 7 was a sectionS-S in FIG. 3 without the 45 degree rotation.Note that kidneyshaped passages 134 and 137 in FIG. 8 again correspondrespectively to passages 134 and 137' in FIG. 3. Exhaust ports 77 and 78are shown in FIG. 8 connected by a passage 177 which does not interceptpassages 134 and 137. The passage 79 of FIG. 4 and is again shown inFIGS. 6, 7'and 8. Cylinder port 133 is shown in FIGS. 4, 6 and 8.

OPERATION OF THE VALVE SHOWN IN FIGS. 4

I ANDS When winding95 is deenergized, spring 93 keeps valve disc 82resting on seat 81 and valve disc 85 spaced from valve seat 84, spring93 being sufficiently strong to overcome the force of spring 125.

When winding 95 is energized, plunger 89 is moved upwardly. Member 87,fixed to plunger 89, then carries valve disc 82 away from and spacedfrom valve seat 81, and allows spring 125 to cause valve disc 85 toengage and close off the opening in cylinder 83, valve disc 85 thenresting against valve seat 84.

When winding 95 is deenergized after being energized, spring 93 returnsvalve disc 82 into engagement with valve seat 81 and moves valve disc 85downwardly away from valve seat 84 in spaced relation thereto.

OPERATION OF THE VALVE Sl-IOWN IN FIGS. 6 I

AND 7 When windingl54 is deenergized, spring 125' is adequate to keepvalve disc 85 in engagement with valve seat 84, and to hold valve disc155 spaced from valve seat 81.

When winding 154 is energized, plunger 169 lowers and causes member 170to bring valve disc 155 into engagement with valve seat 81, spring 173allowing for overtravel of member 170. At the same time, valve disc 85is lowered and spaced from valve seat 84.

After being energized, if winding 154 is deenergized, spring 125' movesvalve discs 85 and 155 again to the positions'shown in FIG. 6. I

By turning valve 71 upsidedown in a manifold, ports 77 and 78 can beused as inlet ports and ports 74 and 75 may be used; as exhaust ports.The same is true of valve 72 shownin FIG. 7. Valves 71 and 72 may, thus,be described as universal valves. The pressure rating of valve 85 inFIG. 4 may be a predetermined rating the same as that of 'valve 82.Similarly, in FIG. 6, both of valves 85 and 155 may have the same saidpredetermined rating. However,the pressure rating of any one of thesevalves may be made higher than said predetermined rating and higher thanthat of another of the valves by making one of the springs 93, 125 and125' stronger or weaker. This maybe a desirable alternative when all theports 74 and 75 disclosed herein are to be I used only as inlet ports.The same is true when all such ports are to be used only as exhaustports.

In FIG. 4, by making spring 125 weaker or spring 93 stronger, thepressure rating of valve 82 goes up and the pressure rating of valve 85goes down. However, if valve 85 is always used for exhaust, it does notneed a high pressure rating because cylinder pressure helps to keep itclosed anyway.

Conversely, in FIG. 4, by making spring 125 stronger or spring 93weaker, the pressure rating of valve 85 goes up and the pressure ratingof valve 82 goes down. However, if valve 85 is always used as the inletvalve and valve 82 as the exhaust valve, the'lower pressure rating ofvalve 82 does not matter because the cylinder pressure, again, helps tokeep it closed.

The two immediately preceding paragraphs apply analogously to valve 72shown in FIGS. 6 and 7. The pressure ratings of valves and in FIG. 6 maybe made unequal with either one being higher than the other by makingspring 125 either stronger or weaker, respectively.

It is to be noted that the present invention may be practiced bylocating a pair of aligned inlet ports and a pair of aligned exhaustports in positions such that the bore axes thereof both lie in ahorizontal plane rather than a vertical plane as viewed in FIGS. 4, 5, 6and 7.

In another alternative, valve bodies 69 and 70 may have cylinder portsin the bottoms 179 and 180 thereof, respectively, as shown in FIGS. 4and 6, respectively.

What is claimed is: l. A three-way valve comprising: a valve body havingfirst, second and third ports; a first valve seat having an openingtherethrough in communication with said first outside said openingssurrounding and spaced from said first and second valves, respectively,said chambers being in communication with each other and with said thirdport; means actuable to operate said first valve, said body having aplurality of holes therethrough parallel to and substantiallysymmetrical about the said axisof said valves; and a rod for each ofsaid holes mounted between said valves and slidable through said holes,said rods causing said valves to move in tandem by opening said secondvalve when said first valve is closed and vice versa, said rods engagingboth of said valves at positions spaced a radial distance from the axisof said valves greater than the radial distance each corresponding seatis spaced from said two rods and two holes, said first and secondports'having parallel bore axes lying in a first planethrough the axisof said valves, said holes having axes lying in a sec 0nd plane disposedat an angle of approximately 45 relative to said first plane and passingthrough the axis of said valves, said body having two cylindricalpassageways disposed on opposite sides of the axis of said valvesequidistant from the axis of said valves, said passageways havingaxeslying in a third plane normal to said second plane and passingthrough the axis of said valves, each of said passageways being incommunication with both of said chambers; said first valve moving towardsaid second chamber when it moves toward said first seat, said firstvalve including a member, a valve element movably guided in said member,a first spring mounted in said member in a position to bias said firstvalve element toward said first seat, said member including stop meansto prevent movement of said valve element toward said first seat beyonda predetermined limit, a second spring mounted in said body tending to3,815,633 9 l mally holding said second valve closed and said first seatwhen said operator means is actuated, said rods valve open, and operatormeans actuable to close said being fixed to said second valve andabutting said first first valve against the force of said second spring,said valve. first spring allowing said member to overtravel said first

1. A three-way valve comprising: a valve body having first, second andthird ports; a first valve seat having an opening therethrough incommunication with said first port; a second valve seat having anopening therethrough in communication with said second port; first andsecond valves guided in said body in a manner to be moved into and outof engagement with said first and second valve seats, respectively, toclose and to open said first and second valve seat openings,respectively, said valves having a common substantially symmetrical axisextending in the directions of movement thereof, said body having firstand second chambers outside said openings surrounding and spaced fromsaid first and second valves, respectively, said chambers being incommunication with each other and with said third port; means actuableto operate said first valve, said body having a plurality of holestherethrough parallel to and substantially symmetrical about the saidaxis of said valves; and a rod for each of said holes mounted betweensaid valves and slidable through said holes, said rods causing saidvalves to move in tandem by opening said second valve when said firstvalve is closed and vice versa, said rods engaging both of said valvesat positions spaced a radial distance from the axis of said valvesgreater than the radial distance each corresponding seat is spaced fromsaid axis; said holes and rods being cylindrical, there being two rodsand two holes, said first and second ports having parallel bore axeslying in a first plane through the axis of said valves, said holeshaving axes lying in a second plane disposed at an angle ofapproximately 45* relative to said first plane and passing through theaxis of said valves, said body having two cylindrical passagewaysdisposed on opposite sides of the axis of said valves equidistant fromthe axis of said valves, said passageways having axes lying in a thirdplane normal to said second plane and passing through the axis of saidvalves, each of said passageways being in communication with both ofsaid chambers; said fiRst valve moving toward said second chamber whenit moves toward said first seat, said first valve including a member, avalve element movably guided in said member, a first spring mounted insaid member in a position to bias said first valve element toward saidfirst seat, said member including stop means to prevent movement of saidvalve element toward said first seat beyond a predetermined limit, asecond spring mounted in said body tending to bias said second valveclosed, said second spring normally holding said second valve closed andsaid first valve open, and operator means actuable to close said firstvalve against the force of said second spring, said first springallowing said member to overtravel said first seat when said operatormeans is actuated, said rods being fixed to said second valve andabutting said first valve.